UNIFAC法预测甲苯,苯甲醛,苯甲酸体系汽液平衡关系

本文增补和修订了适用于芳烃的ＵＮＩＦＡＣ基因相互作用参数（ａＣＨＯ，ＣＯＯＨ，ａＣＯＯＨ，ＣＨＯ）；（ａＡｃＣＨ２，ＣＨＯ、ａＣＨＣ，ＡｃＣＨ２）；（ａＡｃＣＨ２，ＣＯＯＨ、ａＣＯＯＨ，ＡｃＣＨ２）。将其用于计算甲苯、苯甲醛、苯甲酸体系三对二元ＶＬＥ和预测三元ＶＬＥ数据，均获得令人满意的拟合结果。     

UNIFAC基团贡献法预测混合制冷剂的气液相平衡

将UNIFAC基团贡献法成功地应用于HFCs混合制冷剂的气液相平衡热力学性质的预测.根据资料拟合得到了CH₂、CF₂、F三个主基团的相互作用参数, 用拟合的基团相互作用参数预测了新工质对R32/R227ea、R227ea/R134a和R152a/R227ea及三元混合制冷剂R32/R125/R134a的气液相平衡数据,并与实验进行了对比,两者基本吻合.本工作为今后HFCs混合制冷剂替代和制冷系统研究提供了极有推广价值的物性计算方法和数据,满足了新工质工程设计的要求.     

降低脂肪醇聚氧乙烯醚产品中聚乙二醇含量的研究

脂肪醇聚氧乙烯醚产品生产过程中有少量水分和环氧乙烷发生反应生成聚乙二醇副产物,通过正交试验,探索起始剂含水量、催化剂添加量、反应温度及反应压力对降低脂肪醇聚氧乙烯醚产品中聚乙二醇副产物的影响。     

生物柴油-甲醇-甘油液液相平衡数据的关联与预测

用Othmer-Tobias关联式检验了25～55℃范围内麻疯树油甲酯-甲醇-甘油体系的液液相平衡数据的可靠性.用UNIFAC-LLE、UNIFAC-Dortmund和GSP-LLE模型预测了麻疯树油甲酯-甲醇-甘油三元液液体系的相平衡,按质量分数计的均方偏差为10%～16%.通过调整UNIFAC-LLE中反映体系特征的基团-CH=CH-、-CH2COO-、-OH间的交互作用参数,在25℃、35℃、45℃和55℃下,按质量分数计的均方偏差分别降至2.13%、2.76%、2.65%和8.34%,组分的平均绝对偏差分别为1.83%、2.24%、2.16%和6.17%,预测效果明显改善.     

UNIFAC模型关联碳酸酯合成体系的汽液平衡

利用UNIFAC模型对甲醇氧化羰基合成碳酸二甲酯(DMC)体系中的各组分及DMC与苯酚酯交换合成碳酸二苯酯(DPC)体系中的各组分进行了基团划分.根据实验测定的甲醇-DMC、甲醇-草酸二甲酯(DMO)、DMC-DMO、甲醇-苯酚、DMC-苯酚五组二元物系等温汽液平衡数据,拟合了新基团-OCOO-和其他基团间的UNIFAC相互作用参数,扩充了UNIFAC模型的应用范围.与原基团划分的UNIFAC模型关联结果比较,采用新基团划分法推算得到的汽液平衡数据的计算值与实验值偏差较小,说明新基团划分更合理.     

UNIFAC法研究甲烷气体溶解度

用自建的一套设备测定了甲烷在异丙醇、丙酮、四氢呋喃、环己酮及乙酸甲酯中的高压溶解度。采用UNIFAC法对自测及文献中甲烷在极性纯溶剂中的溶解度数据进行了关联和估算,定义了新基团,并回归出了基团间的交互作用能量参数。结果表明,用文中得到的参数估算甲烷在相关溶剂中的溶解度数据结果良好。     

UNIFAC法关联水和乙二醇的汽液平衡

应用ＵＮＩＦＡＣ模型对水和乙二醇系统的汽液平衡进行了关联,求得了水和乙二醇相互作用参数ａＨ２Ｏ,ＤＯＨ＝－１８,ａＤＯＨ,Ｈ２Ｏ＝－１１０。应用上述模型参数于ＵＮＩＦＡＣ模型,于不同压力下计算了水和乙二醇的汽液平衡与文献值十分相符。     

UNIFAC模型预测乙烯基环己烯-乙烯基降冰片烯气液相平衡数据

以乙烯基环己烯一乙烯基降冰片烯为体系,在低压下,将气相视为理想气体,液相为非理想溶液的情况下,用UNIFAC模型估算了液相活度系数,得到了在8．0kPa下此二元体系的气液平衡数据,并与文献值比较,拟合结果较好。结果表明在缺乏此体系的气液平衡数据时,可以用UNIFAC模型估算作为基础数据,以便顺利进行工程设计。     

环氧乙烷迅猛发展对下游乙氧基化装置格局的影响

随着环氧乙烷项目的迅猛发展,其与日增多的产量很大程度上缓解了市场的需求。同时,这种快速增长的形势对其下游产品更深更广的发展将起到重要的直接推动作用,目前环氧乙烷下游产品逐渐集中在乙醇胺系列、聚乙二醇系列、传统的AEO和TX系列以及新兴的减水剂系列等。通过对当前乙氧基化项目情况的分析,预测未来乙氧基化的发展格局。     

UNIFAC基团贡献法估算甲醇-碳酸二甲酯的汽液相平衡

以甲醇-碳酸二甲酯为实验物系，在考虑了汽、液混合物非理想性的情况下，用UNIFAC基团贡献法估算了液相活度系数，用维里方程求算了汽相逸度系数。并最终给出了此二元物系在不同压力下的汽液相平衡数据，结果表明其共沸组成(甲醇摩尔分数)随压力的增高而增大，当压力从0．1MPa增至1．5MPa时，共沸组成由0．890增加到0．960。最后将常压下的相平衡数据与实验值进行了对比，二者的最大偏差为9．4％。     

UNIFAC模型与PRSV方程相结合预测二元及三元系统汽液相平衡

采用Ｗｏｎｇ和Ｓａｎｄｌｅｒ混合规则，将ＰＲＳＶ立方型状态方程与ＵＮＩＦＡＣ活度系数模型相结合，给出一种预测混合物相平衡热力学性质的方法，并用５４个二元体系和９个三元体系的实验数据做了检验，结果表明，该法可以较好地预测二元及三元体系的汽液相平衡。     

利用~1HNMR和共沸点推算醇/烃体系的汽液平衡数据(英文)

With the energy parameters obtained from 1H nuclear magnetic resonance (NMR) chemical shifts data by local composition model and coupled with azeotropic point, the low-pressure vapor-liquid equilibrium is satisfactorily predicted for alcohol + hexane, alcohol + cyclohexane, and alcohol + benzene binary systems at different temperatures. The relationship between the spectroscopic information and thermodynamic property is presented.     

A method for calculation of vapor-liquid and liquid-liquid equilibria

A new parameter, pseudo temperature (T_p) is introduced to solve two-phase equilibrium calculations. The resulting T_p-method has a single set of equations to describe different phase regions encountered in vapor-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE). It does not require a priori the number of phases existing at equilibrium, and involves a minimization problem having a linear objective function subject to nonlinear constraints, which can be solved by a version of successive linear programming method. T_p-method is tested on typical examples for VLE and LLE, and compared with pseudo pressure (P_p) method of Bullard and Biegler [Computers and Chemical Engineering 17, 95–109 (1993)] for VLE. In each example, several operating conditions are considered to cover both single- and two-phase situations. The results show that T_p-method is successful for both VLE and LLE, and that T_p- and P_p-methods are comparable for VLE.     

Isothermal vapor-liquid equilibria for the binary systems of ethylene glycol monopropyl ether with 2,2-dimethylbutane and 2,3-dimethylbutane

Isothermal vapor liquid equilibria for the binary system of ethylene glycol monopropyl ether with 2,2-dimehylbutane and 2,3-dimethylbutane were measured in a circulating water bath at 303.15, 318.15, and 333.15 K. The apparatus was in-house designed and manufactured. Consistency testing of the apparatus was done by comparing the measured vapor pressures to the calculated vapor pressures from the Antoine equation. The measured systems were correlated with a Peng-Robinson equation of state (PR) combined with Wong-Sandler mixing rule for the vapor phase, and NRTL, UNIQUAC, and Wilson activity coefficient models for the liquid phase. All the measured systems showed good agreement with the correlation results.     

水-醋酸-N-甲基吡咯烷酮体系等压汽液平衡研究

用改进的Rose釜测定了醋酸-N-甲基吡咯烷酮、水-醋酸-N-甲基吡咯烷酮在101.33 kPa下的等压汽液平衡数据。醋酸-N-甲基吡咯烷酮体系的汽液平衡数据通过了热力学一致性检验。用NRTL、W ilson和UNIQUAC模型对醋酸-N-甲基吡咯烷酮体系的汽液平衡数据进行了关联,得到了相应的模型参数。用6组文献报道的水-醋酸体系的NRTL模型参数、4组水-N-甲基吡咯烷酮体系的模型参数及关联得到的醋酸-N-甲基吡咯烷酮体系的模型参数对三元体系的汽液平衡数据进行了预测,筛选出9组较佳的模型参数,获得了较优的预测结果。     

Experimental vapor-liquid equilibria for hydrogen-nitrogen-methane-ethane-ethylene

Isothermal vapor-liquid equilibrium data have been obtained for hydrogen-methane-ethane-ethylene at –250°, –200°, –150°, –100% and –50°F, and for hydrogen-nitrogen-methane-ethane-ethylene at –150°F. Pressures were up to 2000 psia. Prediction methods of Lenoir, Chao-Seader, the Data Book of the American Petroleum Institute, and the Data Book of the Natural Gas Processors Suppliers Association (NGPSA) are compared with the experimental data.     

Measurement,correlation and prediction of binary vapor-liquid equilibria for alcohol-tetrachloroethene systems

Experimental isobaric vapor-liquid equilibria of binary mixtures of tetrachloroethene with ethanol, 2-propanol, 2-butanol and 2-pentanol have been measured at 101.08 kPa. The UNIFAC (Fredenslund et al., 1975), a group contribution model and the activity coefficient models of Margules and Van Laar (as presented by Carlson and Colburn, 1942), Wilson (1964), NRTL (Renon and Prausnitz, 1968) and UNIQUAC (Abrams and Prausnitz, 1975) have been used to predict the vapor composition from measured T-x data of ten binary mixtures of alcohol-tetrachloroethene including these four systems. The average absolute deviation between the experimental and the predicted vapor composition with the UNIFAC model ranges from 0.006 to 0.023 mole fraction and that with the activity coefficient models ranges from 0.003 to 0.038. The maximum deviation in both the cases occurred in the data of 1-propanol (Venkateswara Rao et al., 1980).     

Application of UNIFAC models for prediction of vapor-liquid and liquid-liquid equilibria relevant to separation and purification processes of crude biodiesel fuel

Vapor-liquid equilibrium (VLE) of the methanol-biodiesel (BDF)/glycerin binary system and liquid-liquid equilibrium (LLE) of the water-BDF binary system and the methanol-BDF-glycerin and methanol-water-BDF ternary systems were predicted using several UNIFAC models: the latest original UNIFAC model, Kikic’s model, Fornari’s model, Dortmund-UNIFAC model, and LLE-UNIFAC model. The former VLE and latter LLE are used to design methanol recovery processes and separation and purification processes of crude BDF, respectively. Unfortunately, LLE data on the water-BDF binary system was not available. Instead, solubility of water in fatty acid methyl ester (one of the BDF constituents) was measured. By examining the deviation between predicted and experimental results, we determined which of the UNIFAC models was more useful for the design of those processes as follows: either the original UNIFAC model or Dortmund-UNIFAC model should be used for the methanol recovery process. The LLE-UNIFAC model and Dortmund-UNIFAC model were more useful for the recovery and water-washing processes of crude BDF and purification process of water-washed BDF, respectively.     

Prediction of vapor-liquid equilibria by means of a modified clausius equation of state

The Clausius equation was modified for the calculation of vapor-liquid equilibria in binary and multicomponent systems. In the modification, the three parameters of the equation were considered temperature dependent. Molal volumes of saturated liquid and vapor together with the condition that the fugacities of the vapor and the liquid phase are equal at the condition of equilibrium were used for evaluating the parameters of pure components. Applications were made successfully to systems nitrogen-methane, nitrogen-oxygen, argon-oxygen, nitrogen-argon, argon-methane, carbon dioxide-hydrogen sulfide, carbon-dioxide-propane, hydrogen sulfide-n-butane and nitrogen-argon-oxygen.     

二氯甲烷-甲醇-丙酮-水体系汽液平衡测定和关联

二氯甲烷-甲醇-丙酮-水四元体系常见于化工、医药等行业生产的废液中,该体系分离回收的前提是进行汽液平衡数据的测定。现利用单级循环汽液平衡釜测定了二氯甲烷、甲醇、丙酮、水混合液中的6组二元体系在常压下的汽液平衡数据,同时对其进行了点对点法热力学一致性校验。实验中采用SP-6800型气相色谱仪分析汽液相组成,并运用Matlab中的非线性最小二乘法分别关联6组二元体系的汽液相组成,从而得到6对Wilson模型参数,并计算出相应的汽相组成。此外,还测定了二氯甲烷-甲醇-丙酮-水四元体系在100 kPa下的汽液平衡数据,并用关联出的6对模型参数计算该四元体系的汽液平衡数据。将计算结果与实验结果进行对比,实验值与计算值间的绝对偏差均小于0.05。实验结果表明Wilson模型的拟合精度高,适合于关联二氯甲烷、甲醇、丙酮、水体系。实验和计算结果为萃取精馏分离二氯甲烷、甲醇、丙酮、水混合液提供了一定的基础数据。